The present invention relates to an apparatus and process for filling tubes and, more particularly, to an automated tube filling apparatus and process wherein a continuous flow of filling material is directed into a plurality of tubes.
It has long been known to package merchandise and supplies in tubes. Typical products packaged in tubes include caulk, sealant, silicones, greases, as well as health supplies such as toothpaste, lotion, cleansers, and the like. Thus, there is a significant industry relating to tube filling machinery and techniques.
In the manufacturing arena, such as in the fabrication of aircraft or other large machinery, large amounts of sealant are required throughout the manufacturing process. In this regard, sealant is purchased in bulk containers and thereafter packaged into smaller, more usable quantities. Typically, industry standard tubes are used to package the sealant that are used with pneumatic guns to dispense the sealant on the various components throughout the aircraft or other machinery.
The filling operation is conventionally done by hand, since mixing the filling materials and filling the tubes are often required to be in explosion-proof facilities. A typical filling operation comprises an operator applying a label to an empty tube, filling the tube from a filling nozzle, and applying a cap. It is not unusual to fill 1000+ tubes in an eight hour shift. In many cases the packaging must be done locally because the filling material has a relatively short shelf life and, in some cases, the filled tubes must be stored frozen, which further limits their transportability. Filling over 1000 tubes manually creates a significant risk to the operator in terms of repetitive motion, which may result in carpal tunnel syndrome or other repetitive stress conditions. Manual operation also creates potential for other personal injuries from contact with the filling material or heavy machinery.
Automatic tube filling machines are known in the art, such as machines described in U.S. Pat. Nos. 3,788,035; 5,209,044; and 6,082,077. Other automatic filling machines are sold by Daeyong Filling Machinery of Korea. These conventional machines and others like them, however, suffer from several disadvantages. Specifically, some of these conventional automatic machines are electrically operated and therefore susceptible to igniting fumes during the filling operation by electrical sparks or shorts.
An even greater disadvantage with conventional filling machines is the repeated on/off cycling of the filling material pump, which can cause multi-component filling materials to be inconsistently mixed during the tube filling process. The inconsistently mixed filling material cures irregularly or not at all, which results in insufficient seals or other quality problems. In some cases where the filling material is a sealant used to seal joints in aircraft manufacturing, it has been observed that a substantial amount of the filling material is wasted due to rejections for insufficient seals from inconsistently mixed filling material. Thus, there is a need for an automatic filling machine and process that substantially eliminates inconsistently mixed filling materials during the tube filling process. Preferably, such a machine would also be explosion-proof and simple in construction.
These and other needs are provided by the apparatus for filling tubes according to the present invention. Advantageously, the apparatus of the present invention is able to direct a continuous flow of filling material into a plurality of tubes instead of directing intermittent flows into the tubes. As a result, the filling material is consistently mixed and thus provides an improved seal when the filling material is dispensed from the tube during normal use. As such, quality rejections are reduced and the overall manufacturing process is more efficient.
In particular, an apparatus for filling a plurality of tubes according to one embodiment of the present invention comprises a first filling station and a second a filling station operatively connected to at least one gas supply, such as a conventional shop air supply, wherein each filling station is operable to dispense a filling material into a respective tube. Advantageously, the gas supply is the sole source of power a majority if not all of the moving components of the apparatus, which allows the apparatus of the present invention to be used in an explosion-proof environment. In addition, the filling material dispensed by the filling stations is preferably a multi-component filling material, such as an epoxy-resin or the like.
The apparatus also includes a positioning device capable of moving between a plurality of positions, such as between a first position for receiving one of the plurality of tubes from a tube hopper or the like, and a second position for directing the tube towards the filling stations. In particular, the positioning device moves the tube along a path of travel to a selector, which is operable to selectively direct the tube to either the first filling station or the second filling station depending on which filling station is ready to receive an empty tube.
The filling stations direct a continuous flow of filling material into the tubes. In particular, a predetermined amount of filling material is dispensed into the tube until a sensor is actuated, which causes the continuous flow of filling material to be redirected into another tube. Advantageously, the flow of filling material is continuous so that the filling material is consistently mixed during the process. More specifically, the filling material pump does not intermittently start and stop during the filling process, which can cause inconsistent mixing of the filling material components. By contrast, the filling material pump runs continuously according to the present invention, and the filling material components flow through a static mixer or the like and mix consistently before being dispensed into the empty tubes.
According to one embodiment, the apparatus also includes a label applicator that is positioned proximate a third position of the positioning device. In this regard, the positioning device moves the tubes to the label applicator, where an adhesive-backed label is applied to the outer surface of the tube. In one embodiment, the positioning device includes an actuator that can rotate the tube while the positioning device is in the third position so that the label can be easily applied to the rotating tube. The label applicator can be positioned in several locations along the tubes"" path of travel, and in one embodiment is positioned between the first position and third position of the positioning device.
The apparatus also includes a capping device downstream from the filling stations. The capping device includes a cap supply source, such as a cap hopper, a capping station, and a cap feed system capable of directing and aligning a plurality of caps along a path of travel from the cap supply source to the capping station. In operation, the cap feed system moves the caps along an elevator, such as a moving endless belt. At least one orienting device is located along the elevator or elsewhere along the path of travel. The caps are directed to the capping station where they are applied to the end of the tubes. Advantageously, the capping device is powered solely by at least one fluid supply, such as by a standard shop air line. In particular, an elevator drive is operatively connected to the fluid supply, and in one embodiment the drive includes a clutch that limits torque output of the drive if a cap becomes jammed in the capping device.
The apparatus also comprises several safety devices or safety interlocks that protect the operator and prevent damage to the apparatus. One such safety device is a safety door that must be positioned over the tube hopper such that a pair of interlock members suitably engage either mechanically or proximally. If the safety door is not in place over the hopper, new tubes that are not already in process will not be fed through the apparatus. Another interlock is located at a main door so that the apparatus will not operate when the door is opened, such as by opening a latch and pivoting the door about hinges.
Accordingly, the apparatus of the present invention provides a safe and efficient method of filling tubes that avoids the problems of conventional tube filling devices. The apparatus of the present invention is particularly advantageous when the filling material comprises a plurality of components. In particular, because the apparatus of the present invention directs a continuous flow of filling material into the tubes, the filling material pump does not start and stop during the filling operation. As a result, the filling material is consistently mixed and provides better quality seals and less wasted material.